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implement handshake parsing and creation

This commit is contained in:
Robert Habermeier 2016-11-08 16:57:10 +01:00
parent 4ba4861734
commit 440f5e537f
3 changed files with 342 additions and 22 deletions
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13
ethcore/light/src/net/buffer_flow.rs
View File

@ -171,7 +171,7 @@ pub struct FlowParams {
impl FlowParams {
/// Create new flow parameters from a request cost table,
/// buffer limit, and (minimum) rate of recharge.
pub fn new(costs: CostTable, limit: U256, recharge: U256) -> Self {
pub fn new(limit: U256, costs: CostTable, recharge: U256) -> Self {
FlowParams {
costs: costs,
limit: limit,
@ -179,6 +179,15 @@ impl FlowParams {
}
}
/// Get a reference to the buffer limit.
pub fn limit(&self) -> &U256 { &self.limit }
/// Get a reference to the cost table.
pub fn cost_table(&self) -> &CostTable { &self.costs }
/// Get a reference to the recharge rate.
pub fn recharge_rate(&self) -> &U256 { &self.recharge }
/// Estimate the maximum cost of the request.
pub fn max_cost(&self, req: &Request) -> U256 {
let amount = match *req {
@ -253,7 +262,7 @@ mod tests {
use std::thread;
use std::time::Duration;
let flow_params = FlowParams::new(Default::default(), 100.into(), 20.into());
let flow_params = FlowParams::new(100.into(), Default::default(), 20.into());
let mut buffer = flow_params.create_buffer();
assert!(buffer.deduct_cost(101.into()).is_err());

2
ethcore/light/src/net/mod.rs
View File

@ -97,7 +97,7 @@ pub struct LightProtocol {
genesis_hash: H256,
mainnet: bool,
peers: RwLock<HashMap<PeerId, Peer>>,
pending_requests: RwLock<HashMap<usize, Requested>>,
pending_requests: RwLock<HashMap<usize, Request>>,
req_id: AtomicUsize,
}

349
ethcore/light/src/net/status.rs
View File

@ -16,9 +16,75 @@
//! Peer status and capabilities.
use rlp::{RlpStream, Stream, UntrustedRlp, View};
use rlp::{DecoderError, RlpDecodable, RlpEncodable, RlpStream, Stream, UntrustedRlp, View};
use util::{H256, U256};
use super::buffer_flow::{CostTable, FlowParams};
// recognized handshake/announcement keys.
// unknown keys are to be skipped, known keys have a defined order.
// their string values are defined in the LES spec.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum Key {
ProtocolVersion,
NetworkId,
HeadTD,
HeadHash,
HeadNum,
GenesisHash,
ServeHeaders,
ServeChainSince,
ServeStateSince,
TxRelay,
BufferLimit,
BufferCostTable,
BufferRechargeRate,
}
impl Key {
// get the string value of this key.
fn as_str(&self) -> &'static str {
match *self {
Key::ProtocolVersion => "protocolVersion",
Key::NetworkId => "networkId",
Key::HeadTD => "headTd",
Key::HeadHash => "headHash",
Key::HeadNum => "headNum",
Key::GenesisHash => "genesisHash",
Key::ServeHeaders => "serveHeaders",
Key::ServeChainSince => "serveChainSince",
Key::ServeStateSince => "serveStateSince",
Key::TxRelay => "txRelay",
Key::BufferLimit => "flowControl/BL",
Key::BufferCostTable => "flowControl/MRC",
Key::BufferRechargeRate => "flowControl/MRR",
}
}
fn from_str(s: &str) -> Option<Self> {
match s {
"protocolVersion" => Some(Key::ProtocolVersion),
"networkId" => Some(Key::NetworkId),
"headTd" => Some(Key::HeadTD),
"headHash" => Some(Key::HeadHash),
"headNum" => Some(Key::HeadNum),
"genesisHash" => Some(Key::GenesisHash),
"serveHeaders" => Some(Key::ServeHeaders),
"serveChainSince" => Some(Key::ServeChainSince),
"serveStateSince" => Some(Key::ServeStateSince),
"txRelay" => Some(Key::TxRelay),
"flowControl/BL" => Some(Key::BufferLimit),
"flowControl/MRC" => Some(Key::BufferCostTable),
"flowControl/MRR" => Some(Key::BufferRechargeRate),
_ => None
}
}
fn is_recognized(s: &str) -> bool {
Key::from_str(s).is_some()
}
}
/// Network ID structure.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[repr(u32)]
@ -29,6 +95,66 @@ pub enum NetworkId {
Testnet = 0,
}
impl NetworkId {
fn from_raw(raw: u32) -> Option<Self> {
match raw {
0 => Some(NetworkId::Testnet),
1 => Some(NetworkId::Mainnet),
_ => None,
}
}
}
// helper for decoding key-value pairs in the handshake or an announcement.
struct Parser<'a> {
pos: usize,
rlp: UntrustedRlp<'a>,
}
impl<'a> Parser<'a> {
// attempt to parse the next key, value pair, and decode the value to the given type.
fn expect<T: RlpDecodable>(&mut self, key: Key) -> Result<T, DecoderError> {
self.expect_raw(key).and_then(|item| item.as_val())
}
// attempt to parse the next key, value pair, and returns the value's RLP.
fn expect_raw(&mut self, key: Key) -> Result<UntrustedRlp<'a>, DecoderError> {
loop {
let pair = try!(self.rlp.at(self.pos));
let k: String = try!(pair.val_at(0));
let k = match Key::from_str(&k) {
Some(k) => k,
None => {
// skip any unrecognized keys.
self.pos += 1;
continue;
}
};
if k == key {
self.pos += 1;
return pair.at(1)
} else {
return Err(DecoderError::Custom("Missing expected key"))
}
}
}
}
// Helper for encoding a key-value pair
fn encode_pair<T: RlpEncodable>(key: Key, val: &T) -> Vec<u8> {
let mut s = RlpStream::new_list(2);
s.append(&key.as_str()).append(val);
s.out()
}
// Helper for encoding a flag.
fn encode_flag(key: Key) -> Vec<u8> {
let mut s = RlpStream::new_list(2);
s.append(&key.as_str()).append_empty_data();
s.out()
}
/// A peer status message.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Status {
@ -72,26 +198,80 @@ impl Default for Capabilities {
}
}
impl Capabilities {
/// Decode capabilities from the given rlp stream, starting from the given
/// index.
fn decode_from(rlp: &UntrustedRlp, start_idx: usize) -> Result<Self, DecoderError> {
let mut caps = Capabilities::default();
/// Attempt to parse a handshake message into its three parts:
/// - chain status
/// - serving capabilities
/// - buffer flow parameters
pub fn parse_handshake(rlp: UntrustedRlp) -> Result<(Status, Capabilities, FlowParams), DecoderError> {
let mut parser = Parser {
pos: 0,
rlp: rlp,
};
for item in rlp.iter().skip(start_idx).take(4) {
let key: String = try!(item.val_at(0));
let status = Status {
protocol_version: try!(parser.expect(Key::ProtocolVersion)),
network_id: try!(parser.expect(Key::NetworkId)
.and_then(|id: u32| NetworkId::from_raw(id).ok_or(DecoderError::Custom("Invalid network ID")))),
head_td: try!(parser.expect(Key::HeadTD)),
head_hash: try!(parser.expect(Key::HeadHash)),
head_num: try!(parser.expect(Key::HeadNum)),
genesis_hash: parser.expect(Key::GenesisHash).ok(),
last_head: None,
};
match &*key {
"serveHeaders" => caps.serve_headers = true,
"serveChainSince" => caps.serve_chain_since = Some(try!(item.val_at(1))),
"serveStateSince" => caps.serve_state_since = Some(try!(item.val_at(1))),
"txRelay" => caps.tx_relay = true,
_ => continue,
}
}
let capabilities = Capabilities {
serve_headers: parser.expect_raw(Key::ServeHeaders).is_ok(),
serve_chain_since: parser.expect(Key::ServeChainSince).ok(),
serve_state_since: parser.expect(Key::ServeStateSince).ok(),
tx_relay: parser.expect_raw(Key::TxRelay).is_ok(),
};
Ok(caps)
let flow_params = FlowParams::new(
try!(parser.expect(Key::BufferLimit)),
try!(parser.expect(Key::BufferCostTable)),
try!(parser.expect(Key::BufferRechargeRate)),
);
Ok((status, capabilities, flow_params))
}
/// Write a handshake, given status, capabilities, and flow parameters.
pub fn write_handshake(status: &Status, capabilities: &Capabilities, flow_params: &FlowParams) -> Vec<u8> {
let mut pairs = Vec::new();
pairs.push(encode_pair(Key::ProtocolVersion, &status.protocol_version));
pairs.push(encode_pair(Key::NetworkId, &(status.network_id as u32)));
pairs.push(encode_pair(Key::HeadTD, &status.head_td));
pairs.push(encode_pair(Key::HeadHash, &status.head_hash));
pairs.push(encode_pair(Key::HeadNum, &status.head_num));
if let Some(ref genesis_hash) = status.genesis_hash {
pairs.push(encode_pair(Key::GenesisHash, genesis_hash));
}
if capabilities.serve_headers {
pairs.push(encode_flag(Key::ServeHeaders));
}
if let Some(ref serve_chain_since) = capabilities.serve_chain_since {
pairs.push(encode_pair(Key::ServeChainSince, serve_chain_since));
}
if let Some(ref serve_state_since) = capabilities.serve_state_since {
pairs.push(encode_pair(Key::ServeStateSince, serve_state_since));
}
if capabilities.tx_relay {
pairs.push(encode_flag(Key::TxRelay));
}
pairs.push(encode_pair(Key::BufferLimit, flow_params.limit()));
pairs.push(encode_pair(Key::BufferCostTable, flow_params.cost_table()));
pairs.push(encode_pair(Key::BufferRechargeRate, flow_params.recharge_rate()));
let mut stream = RlpStream::new_list(pairs.len());
for pair in pairs {
stream.append_raw(&pair, 1);
}
stream.out()
}
/// An announcement of new chain head or capabilities made by a peer.
@ -105,6 +285,137 @@ pub struct Announcement {
head_td: U256,
/// reorg depth to common ancestor of last announced head.
reorg_depth: u64,
/// updated capabilities.
new_capabilities: Capabilities,
/// optional new state-serving capability
serve_state_since: Option<u64>,
/// optional new chain-serving capability
serve_chain_since: Option<u64>,
// TODO: changes in buffer flow?
}
#[cfg(test)]
mod tests {
use super::*;
use super::super::buffer_flow::FlowParams;
use util::{U256, H256, FixedHash};
use rlp::{RlpStream, Stream ,UntrustedRlp, View};
#[test]
fn full_handshake() {
let status = Status {
protocol_version: 1,
network_id: NetworkId::Mainnet,
head_td: U256::default(),
head_hash: H256::default(),
head_num: 10,
genesis_hash: Some(H256::zero()),
last_head: None,
};
let capabilities = Capabilities {
serve_headers: true,
serve_chain_since: Some(5),
serve_state_since: Some(8),
tx_relay: true,
};
let flow_params = FlowParams::new(
1_000_000.into(),
Default::default(),
1000.into(),
);
let handshake = write_handshake(&status, &capabilities, &flow_params);
let (read_status, read_capabilities, read_flow)
= parse_handshake(UntrustedRlp::new(&handshake)).unwrap();
assert_eq!(read_status, status);
assert_eq!(read_capabilities, capabilities);
assert_eq!(read_flow, flow_params);
}
#[test]
fn partial_handshake() {
let status = Status {
protocol_version: 1,
network_id: NetworkId::Mainnet,
head_td: U256::default(),
head_hash: H256::default(),
head_num: 10,
genesis_hash: None,
last_head: None,
};
let capabilities = Capabilities {
serve_headers: false,
serve_chain_since: Some(5),
serve_state_since: None,
tx_relay: true,
};
let flow_params = FlowParams::new(
1_000_000.into(),
Default::default(),
1000.into(),
);
let handshake = write_handshake(&status, &capabilities, &flow_params);
let (read_status, read_capabilities, read_flow)
= parse_handshake(UntrustedRlp::new(&handshake)).unwrap();
assert_eq!(read_status, status);
assert_eq!(read_capabilities, capabilities);
assert_eq!(read_flow, flow_params);
}
#[test]
fn skip_unknown_keys() {
let status = Status {
protocol_version: 1,
network_id: NetworkId::Mainnet,
head_td: U256::default(),
head_hash: H256::default(),
head_num: 10,
genesis_hash: None,
last_head: None,
};
let capabilities = Capabilities {
serve_headers: false,
serve_chain_since: Some(5),
serve_state_since: None,
tx_relay: true,
};
let flow_params = FlowParams::new(
1_000_000.into(),
Default::default(),
1000.into(),
);
let handshake = write_handshake(&status, &capabilities, &flow_params);
let interleaved = {
let handshake = UntrustedRlp::new(&handshake);
let mut stream = RlpStream::new_list(handshake.item_count() * 3);
for item in handshake.iter() {
stream.append_raw(item.as_raw(), 1);
let (mut s1, mut s2) = (RlpStream::new_list(2), RlpStream::new_list(2));
s1.append(&"foo").append_empty_data();
s2.append(&"bar").append_empty_data();
stream.append_raw(&s1.out(), 1);
stream.append_raw(&s2.out(), 1);
}
stream.out()
};
let (read_status, read_capabilities, read_flow)
= parse_handshake(UntrustedRlp::new(&interleaved)).unwrap();
assert_eq!(read_status, status);
assert_eq!(read_capabilities, capabilities);
assert_eq!(read_flow, flow_params);
}
}